Fluid pressure pump



April 29, 1941. G. H. TESSMER 2,240,356

FLUID PRESSURE PUMP Filed July 1, 1959 -Z33. U619 Zor 601 0 012 JZ 1651112987 Patented Apr. 29, 1941 FLUID PRESSURE PUMP Gordon H. Tessmer,Minneapolis, Min-11., assignor to Warner Manufacturing Company,Minneapolis, Minn., a corporation of Minnesota Application July 1,.1939, Serial No. 282,562

1 Claim.

My invention provides an extremely simple and highly efficientfluid-pressure pump of the rotary or centrifugal type, having thevarious improved features of construction and operation hereinafterdescribed and defined in the claim.

The improved pump is capable of being made in various diiferent sizesand put to various different uses, but has been especially designed andparticularly adapted for use in centrifugal pumps driven by smallelectric motors. Selistarting electric motors, as is well known, haverelatively low starting torques, and this is especially true in respectto small electric motors.

Leakage between the motor driven pump shaft and the pump casing hashitherto generally been prevented by packings which must engage the pumpshaft with very considerable friction to prevent leakage. Thefriction ofsuch packing has-hitherto made necessary the use of an electric motor ofgreater power than would be required after the motor has once beenstarted.

A major feature of my invention is directed to the provision of asubstitute for the ordinary packing, which, while efficient to preventleakage, will ofi'er but very slight friction to the starting of themotor. This feature is met by the use of a sealing diaphragm throughwhich the pump or motor shaft is passed into the pressure chamber of thepump. The sealing diaphragm and the co-operating contacting elements areof novel construction and arrangement as will presently appear. Thevarious novel features of the invention will be made clear by theconcrete illustration of a specific problem for which the invention hasbeen designed and for which it has been commercially employed, and whichdevice is illustrated in the accompanying drawing wherein likecharacters indicate like parts throughout the several views.

Referring to the drawing:

Fig. 1 is an elevation showing the improved pump and parts of anelectric motor for driving the rotary element of the pump;

Fig. 2 is a section taken on the line 22 of Fig. 1 showing the parts ona larger scale than in Fig. 1;

Fig. 3 is a vertical section taken through the pump on the line 3--3 ofFig. 2; and

Fig. 4 is a perspective showing in detail the rotary element of thepump.

The pump casing, as shown, is made of two elements, to wit; 6 and I. Themain pump element 6 is formed with a pressure chamber 8 with an intakepassage 9 and with a discharge passage ill. The intake passage 9 will beassumed to be connected to a source .of liquid supply such as anelevated tank, not shown, by a pipe II. The outlet passage In isconnected to an upright stack l2.

The section 1 is in the nature of a head detachably secured to the mainsection 6 by machine screws I3 or the like. This head I, in thestructure illustrated, is bolted to or otherwise rigidly secured to thecasing M of an electric motor having an extended armature shaft 15. Thehead 1 is formed with a large axial passage l6 which may be nearly orabout as large as the pressure chamber 8.. i

A sealing diaphragm H is clampedat its outer edge, with a fluid tightjoint, between the sections 6 and 1 and is formed with an axial passage18 through which the armature shaft l5 projects into the pressurechamber 8. Within the pressure chamber 8 the armature shaft I5 isprovided with a head which, as shown, is in the form of a cap-likesealing head l9 telescoped on to the same and rigidly secured thereto bya machine screw 20. The cap-like head is provided with a propellingblade 2| that may be variously formed but, as shown, is wrapped aroundand welded or otherwise rigidly secured to the cap with its bladeprojecting tangentially therefrom.

The numeral 22 indicates a packing clamped between the inner end of theshaft [5 and the end of the head Ill. The large or outer end of the headI9 acts as a sealing surface against the diaphragm and is in the planethat is perpendicular to the axis of the shaft and has direct frictionalengagement with the inner portion of the diaphragm IT. The end of thecaplike head I9 is yieldingly held in frictional contact with thediaphragm, by suitable means, such as a coil spring 23 compressedbetween the motor casing and a pressure washer 24 that directly engagesthe radially inner portion of the diaphragm.

To permit slight wobbling of the shaft IS in case that should occur, theaxial perforation l8 of the diaphragm is made large enough to amplyclear the shaft l5. To permit slight axial move ments of the armatureshaft and parts carried thereby, if such movement should occur, thediaphragm I1 is made of at least slightly flexible material. The kind ofmaterial used in the diaphragm will depend a good deal upon the natureof the liquid that is being used in the pump and should be such as notto be chemically acted upon by such liquid.

In practice I have used this pump for the pumping of kerosene whichrequires a very tight joint to prevent leakage; and. for the purposehave made the diaphragm of material such as generally known as Dupremebut various other materials may be employed.

The tension of the spring of yielding element 23 should be such and onlyslightly in excess of that required to seal the joint between thediaphragm and the head of the shaft under the maximum pressure that canbe produced by the action of the pump. This may be accomplished inseveral ways. For example, the propeller blade 2| should be of such sizeand clearance in the pressure chamber that no matter how fast it isrotated by the motor, it cannot produce sufiicient pressure to overcomethe spring and produce a leaking joint.

For a further illustration of a specific use of the pump for pumpingkerosene, a small selfstarting electric motor was employed in connectionwith the pump in which at maximum speed the pump would elevate thekerosene to a maximum of only twelve inches. Then in the column l2, theoverflow or relief pipe 25 was at an elevation to permit overflow whenthe column of fluid reached an altitude of eight inches. The tension ofthe spring 23 was then set or the spring was so designed that it wouldkeep the flexible diaphragm pressed against the head I9 under pressureof a column very slightly in excess of twelve inches. 7 7

With thisarrangement, under normal conditions, there would be maintaineda column of flowing liquid at an altitude of eight inches, and even ifthe circulating pipe should be clogged, the diaphragm would not beunseated nor leakage produced. With this arrangement the frictionbetween the head 19 and the diaphragm is reduced to the minimum and willnot impede to any great extent the starting of the relatively smallmotor.

If the pump shaft should, because of wear or for lack of accurateadjustment, be capable of slight axial movement, that movement would betaken up by the resilience of elasticity of the diaphragm. If the shaftshould wobble slightly, the sealing surface of the sealing head I9, inaddition to rotating against the diaphragm, would simply slipeccentrically against the face of the diaphragm without producing anymaterial increased friction. The arrangement described accomplishes allof the desirable results above indicated.

"peller and casing.

From the foregoing it follows that the preferred form of the deviceillustrated in the drawing is capable of various modifications withinthe scope of the invention herein described and claimed.

What I claim is:

A fluid pump of the circulator type comprising a casing having acylindrical pressure chamber open at one end of said casing and beingclosed at its opposite end by an inwardly recessed casing wall, an inletport leading axially into said chamber through the recess in said endwall, an outlet leading radially through said casing from thecylindrical wall of said chamber, a flexible diaphragm secured over theopen end of said chamber and providinga flexible end wall therefor, arotary shaft extending through said diaphragm and terminating withinsaid chamber, a hub mounted on said shaft within said chamber and havinga radially extending flange in frictional sealing engagement with theinner side of said diaphragm, a propeller of materially less dimensionsthan said pressure chamber mounted rounding said shaft and yieldablyengaging the outer side of said diaphragm to maintain a fluid sealbetween said shaft and diaphragm under relative axial and lateralvibrations of said pro- GORDON H. TESSMER.

